A2.12 Increased CXCR5 B cell expression, CXCL13 and SCD23 serum levels in untreated early rheumatoid arthritis patients support B cell activation since the initial phase of the disease

Background and objectives B-cells play several important roles in rheumatoid arthritis (RA) pathogenesis, namely through autoantibody production, antigen presentation and T cell activation, but few studies have been performed in untreated early RA patients. Therefore, the main goal of this study was to characterise B-cell phenotype and B-cell gene expression levels since early RA onset in comparison with the chronic phase of the disease. Materials and methods Blood samples were collected from untreated early RA (ERA) patients ( Results The frequency of total CD19 + B-cells in circulation was similar between controls and patients’ groups, but established RA had significantly increased frequencies of double negative (IgD-CD27-) B-cells in comparison with controls. CXCR5 B-cell expression was significantly increased in both ERA and established RA in comparison with controls, but no significant differences were observed in BAFF-R, TACI, BCMA, CD69, CD86, HLA-DR, TLR9, CD95, IgM and CD5 B-cell expression between all groups analysed. Furthermore, alterations in B-cell gene expression levels were found in BAFF-R, TACI, TLR9, FcγRIIB, BCL-2, BLIMP-1 and β2M in ERA and established RA patients when compared to controls, but no significant differences were detected in AID, BCMA, CXCR5, TLR7 and TLR10 B-cell gene expression between all groups. In addition, CXCL13 and sCD23, but not BAFF serum levels, were significantly increased since early RA. Conclusions CXCR5 B-cell expression and CXCL13 serum levels are significantly increased in untreated early RA (